5 Guides in This Module
The Math of Betting
The concepts that separate winners from losers: implied probability, the vig, expected value, fair odds, and closing-line value. No advanced math required.
Beginner 6 min
Implied Probability & Converting Odds
How to turn any betting odds into a probability, why it matters, and how to spot when a price is better than the real chance of winning.
Beginner 7 min
The Vig (Juice): How Sportsbooks Make Money
What the vig is, how to calculate a book's margin, what a dime line means, and why reducing the juice you pay is one of the fastest ways to bet more profitably.
Intermediate 7 min
Expected Value (EV) in Betting
What expected value means, how to calculate the EV of a bet, and why +EV betting is the only mathematically proven way to win long-term.
Intermediate 6 min
Fair Odds & De-Vigging Explained
How to strip the vig out of a market to reveal the true, fair probability - the reference every value bet is measured against.
Intermediate 6 min
Closing Line Value (CLV): The #1 Skill Metric
What CLV is, why beating the closing line predicts long-term profit better than your win rate, and how to track it.
The Math of Betting — Key Questions Answered
What is implied probability?
It's the probability of winning that a set of betting odds represents. For decimal odds, it's simply 1 divided by the decimal price. A price of 2.00 implies a 50% chance.
What is the vig in betting?
The vig (or juice) is the margin a sportsbook builds into its odds. It's why both sides of a market add up to more than 100%, and it's the book's main source of profit.
What does +EV mean?
Positive expected value - a bet whose price is better than the true probability of winning justifies, so it profits on average over many repetitions even if it loses individual bets.
What are no-vig or fair odds?
The odds a market would offer with zero margin. You get them by removing the vig so the two sides' probabilities add up to exactly 100%, revealing the true implied probability.
What is closing line value?
CLV compares the odds you bet at to the final (closing) odds the market settles on. Beating the closing line consistently is the strongest indicator that you're making +EV bets.